Hiroshi Fujimoto and Motoo Abiko used to write together under the pen name of "Fujiko Fujio". After many successful comics (among which the notorious Doraemon), they broke up in 1987. Motoo Abiko continued under the name of "Fujiko Fujio (A)" and Hiroshi Fujimoto under the name of "Fujiko Fujio (F)", later renamed to "Fujiko F. Fujio".